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Letters Patent No. 79,182, dated June 23, 1868.

IMPROVEMENT tu STEAM SAFETY-Vanves.

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TO ALL WHOM IT MAY CONGERN:

Be it known that I, EHlAsHcROFT, of Lynn, county ofEsscX, and State ofMassachusetts, have invented a new and useful Improvement in Steam Safety-Valves; and'I do hcrebyvdeclare that the following is a full and exact description thereof, reference being had to the accompanying drawing, and to the letters of reference marked thereon,l in which like letters represent like parts.

Figure l is a vertical-,and centralrsection of my invention. I

` To enable others skilled inthe art to make and use my invention, I will proccedto describe its construction and operation. A i i My present invontion'hmay be considered as an vimprovement upon that for which Letters Patent ot' the United States were issued to me on the 21st day of April, 1868.

Intlie practical opeia'igionof the safety-valve referred to in said patent, above referred to, it was found that the sudden action of the valve had the tendency of drawing or lifting'a considerable quantity of water, and carrying it from the boiler with the escaping steam.

One purpose of my present invention is to remedy this defect, and to this end I provide the lower part of the opening or steam-chamber a of the hollow base, b, of' the valve with a foraminous diaphragm, c, suitably fixed therein, and through which the steam passes i'rom the boiler to Ithe valve.

In its passage through the diaphragm c, the steam is wirc-drawn, as it is termed by engineers, or caused to separate from any great quantity of moisture or water takenup by it, which will not pass through such diaphragm. l v

Another portion of my inventionis to provide a means whereby, upon fracture or failure of the spring of the valve, the escape of steam therefrom is out oi. p

In carrying out this part of my invention, I screw or otherwise secure to the lower end of the valvestem d ofthe primary valve g, an auxiliary valve, e, and I also form in the base ofthe steam-chamber or passage, a, of the valve anl auxiliary valveseat,f, disposed below the primary valve, and valve-scat g or L, as represented, the two valves being so arranged, with respectl'to each other 'and their seats, that when the primary valve g is controlled and operated as designed by the valve=spring z', the auxiliary valve e shall be and remain open, so as not to obstruct the action of' the steam upon the primary and acting valveg.

The said auxiliary valve e is designed to perform two oirices, viz, first,` to break a current 'of' water being drawn by and with the escaping steam into the open air, upon the sudden action of the steam upon the primary valve g; second, to act as a stop safety-valve, in the event of the fracture or breaking of thc springt' of the valve g. 4 p l Should the spring z', which serves to depress the 'primary valve, become broken or '(iisabled, thc upward pressure of the steam upon the'lowcr and auxiliary valve e,`will force such valve tightly up to its seat, and by this means prevent the escape and loss of steam, which would otherwise find free vent into the open air, and perhaps lead to fatal results. i Y Y v By referring to the accompanying drawing, it will be seenthat the primary valve g is formed with a surA roundingdip or ledge, c, the valve thus provided being enclosed by a second lip or ledge, Z, formed upon or around its valve-seat, as vshown in the drawing. The ledge k has thc effect, upon the raising of the valve, of causing an accumulation of steam within the enclosure, m, formed by it, 'until such accumulation has acquired the power of lifting the valve, which it does with a sudden concussion or snap. -v

The lip lor ledge l'serves the purpose of preventing too great lateral spreading of the steam as it escapes in It will further be perceived, on referring to the drawing, that I form in the bearing-face of the primary valve iq, an annular groove or recess, n. The water resulting from the condensation of steam collects within this recess or groove, and serves as a packing between the valve and its scat, when closed.

Having thus described my invention, what I claim, as new, and desire to secure by Letters Patent of the United States, is-

1. The combination of the diaphragm c, valve e, as herein set forth.

2. The construction of the valves g and c, valv@l e, openingf, spring i, and diaphragm c, su

valve g, stem d, with the base, Z); and spring i', substantially and the arrangement caf-the recessesr n, and` fm, ledges lc and Z,

bstantially as herein setforth. v y

' E. H. ASHCROFT.

- Witnesses:

EDWIN J. WRIGHT, CHARLES E. As-nenonr. 

